Cryptotanshinone is known as a quinoid diterpene extracted from the root of Salvia miotiorrhiza bunge and can show outstanding anticancer activities. In the present study, we explored the mechanism of action of cryptotanshinone, and its potential efficacy as a promising therapy for the treatment of non-small cell lung cancer (NSCLC) cell line (A549) in vitro. A549 cells were incubated with cryptotanshinone and cell proliferation and apoptosis were investigated using MTT, LDH, ROS, Annexin-V-FITC assays. The expression levels of lncRNA HOTAIR and p-Akt were quantified by quantitative real-time PCR (qPCR) and western blot, respectively. The results showed that cryptotanshinone mitigated cell proliferation in a dose and time-dependent manner through a significant increase in LDH release, ROS production, and apoptosis in A549 lung cancer cells. Treatment of A549 cells with cryptotanshinone also led to downregulation of lncRNA HOTAIR and protein level of p-Akt. Furthermore, the anticancer effect of cryptotanshinone was inhibited in the presence of NAC as a potential antioxidant. In general, it was found that cryptotanshinone is an effective agent in preventing lung cancer cells growth through downregulation of HOTAIR and p-Akt expression which is partially due to high level of ROS.